Key On Engine Off (KOEO) On-Demand Self-Test
WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The KOEO on-demand self-test is a functional test of the PCM or the TCM, and is carried out on demand with the key in the ON position and the engine OFF. This test carries out checks on certain input and output circuits. A fault must be present at the time of testing for the KOEO self-test to detect the fault. When a fault is detected, a DTC is output on the data link at the end of the test when requested by a scan tool. The KOEO on-demand self-test can be executed with the gear selector in PARK only.